Leucothrix arctica sp. nov., isolated from Arctic seawater.

ABSTRACT

A Gram-stain-negative, non-motile, oxidase- and catalase-positive, rod-shaped bacterium was isolated from a coastal seawater sample from the Arctic Circle and designated strain IMCC9719T. On the basis of 16S rRNA gene sequence analysis, it was shown that strain IMCC9719T belonged to the genus Leucothrix and was closely related to the type strains of Leucothrix pacifica (97.6 % similarity) and Leucothrix mucor (95.1 %), while the strain shared <90.6 % sequence similarity with other bacterial species. The average nucleotide identity and genome-to-genome distance values between strain IMCC9719T and L. pacifica JCM 18388T were 71.7 and 16.9 %, respectively. The DNA G+C content of strain IMCC9719T was 43.5 mol%. Optimum growth of strain IMCC9719T was observed at 15 °C, at pH 7.5-8.5 and in the presence of 2.0-2.5 % (w/v) NaCl. The major fatty acids were summed feature 3 (C16  1ω7c and/or C16  1ω6c), summed feature 8 (C18  1ω6c and/or C18  1ω7c) and C16  0. Cells of strain IMCC9719T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified polar lipid, an unidentified aminophospholipid and two unidentified phospholipids. The major respiratory quinone was ubiquinone-8 (Q-8). Based on the taxonomic data collected in this study, strain IMCC9719T represents a novel species of the genus Leucothrix, for which the name Leucothrix arctica sp. nov. is proposed. The type strain is IMCC9719T (=KACC 18010T=NBRC 110382T).